In today's computer networks, sharing data among devices has become desirable if not essential. Not only does the shared data need to be replicated on each device, but the set of replicated data must be synchronized so that changes made to one replica are reflected in all the others. Synchronization enables many users to work with their own local copy of shared data but have the shared data updated as if they were working on a single, centralized database. For shared data applications where users are geographically widely distributed, replication and synchronization are often the most efficient methods for effectively utilizing shared data.
In addition to desktop computers (including workstations and servers), modern computing environments often include lightweight mobile computing devices that fit into a pocket, purse, or day planner. The memory and processor speeds of mobile devices are limited in comparison with desktop computers. A mobile device may, for example, have a processor running at two hundred megahertz and contain sixty-four megabytes of combined operational and storage memory. The operational memory holds the instructions from an application that the processor executes and the data that those instructions work with. The storage memory holds applications and data not in use by the processor. A desktop computer on the other hand may have a processor operating at two gigahertz, have two hundred-fifty six megabytes of operational memory, and have thirty gigabytes of storage memory. These numbers are of course relative. As technology progresses, the numbers will improve. However, it is expected that the computing power of a desktop most always will be greater than that of a mobile device.
The processor and memory constraints of mobile devices prevent them from utilizing more sophisticated applications available to desktop computers. For example, a word processor designed for a mobile device will typically not have the number of features available to a word processor designed for a desktop computer. The desktop's word processor will likely have the ability to format different sections of a document differently. Multiple fonts may be used. Different margins may be applied to different sections. The document may include one or more bulleted lists. The possibilities go on. The word processor on a mobile device, however, may function more like a simple text editor lacking anything but basic formatting functions. Consequently, a document created using a desktop word processor cannot be accessed by a mobile word processor without being converted to a simpler format. The conversion however removes all formatting from the document not compatible with the mobile word processor. When the document is returned to the desktop word processor, it must be reformatted.
Sharing electronic mail between desktop and mobile devices can also pose difficulties. Electronic mail editors designed for desktop computers are capable of multiple functions. In addition to sending text messages to one or more intended recipients, they are capable of sending meeting notifications and invitations, interacting with calendaring applications to schedule meetings, and managing task lists. While mobile devices are capable of generating text messages, many cannot create electronic mail. If they can, many still cannot send specialized messages such as a meeting notification or invitation let alone interact with a calendaring application or manage a task list.
The limitations of mobile devices often prevent them from interacting effectively with more powerful computing devices such as desktop computers.